1. Field of the Invention
This invention relates to a carriage device for moving and positioning a magnetic head, and more particularly to an improved magnetic head carriage device for moving a magnetic head to a prescribed position on a magnetic disk or other recording/reproducing medium and causing the magnetic head to effect the required writing/reading operation at that position.
2. Description of the Prior Art
The magnetic disk drive is well known as a magnetic memory device. Because the magnetic disk drive is capable of storing prescribed alphanumerics etc. in the form of magnetic signals in the magnetic layer on a magnetic disk, it is utilized as an internal memory for the computer. Further because it is capable of storing picture images in a magnetic disk, it can be used as a memory unit in a magnetic camera.
In the past, hard disks were used with magnetic disk drives of this kind. In recent years, floppy disks have gained wide acceptance since they permit miniaturization of the disk drives and make the disk drives easier to operate. These floppy disks even make it possible to provide portable disk drives.
The magnetic disk drive of any of the types described above is generally constructed so that while the magnetic disk is rotated a magnetic head is moved in the radial direction of the magnetic disk and to a prescribed position and, at that position, is allowed to write/read information in a prescribed format in/from a specific track on the surface of the magnetic disk. For the magnetic head to be accurately reciprocated relative to the magnetic disk, the magnetic head is mounted on a carriage. The accuracy with which the magnetic head is positioned at the prescribed position is required to be extremely high. In this sense, the drive mechanism for the carriage is an extremely important factor in determining the characteristics of the device.
As means for driving the carriage, there have been reduced to practice a drive device which transmits the rotation of a stepping motor as with an .alpha.-belt to the carriage and a device which effects precise driving by mechanically combining the carriage with the moving member of a linear motor secured on the base of the device.
The conventional devices based on these operating principles require a carriage supported slidably on the base of the device and a stepping motor or a linear motor disposed independently of the carriage and, consequently, are difficult to miniaturize as a whole. Thus, they have not been able to respond to recent growing demand for further reduction of the volume, thickness and weight of disk drives.